A novel single phase cascaded multilevel inverter for hybrid renewable energy sources

This paper presents a novel single phase cascaded multilevel inverter for renewable energy applications. The proposed inverter consists of two H Bridge inverter connected in cascade. The top H Bridge inverter is a conventional H bridge inverter and is capable of developing three level output whereas the bottom H bridge inverter is a novel inverter which is capable of developing multilevel output. The proposed inverter is driven from a novel hybrid modulation technique, which eliminates the problem of capacitor voltage balancing issues. The proposed novel hybrid modulation technique switches the top inverter switches at high frequency and the bottom inverter switches at low frequency. The proposed inverter can be fed from any renewable energy source. In this paper, the top inverter is fed from PV arrays where as the bottom inverter is fed from wind turbine. The proposed inverter has many advantages such as; it has minimum number of power electronic devices, minimum conduction and switching losses, improved efficiency and minimum voltage stress on the devices. The proposed inverter fed from renewable energy sources is simulated in MATLAB/SIMULINK environment. To validate the simulation results a laboratory prototype is also built. The entire hardware setup is controlled by using FPGA-SPATRAN 3A DSP board.